1. Field of the Invention
The present invention relates to a disk device having with a transfer mechanism for conveying a disk inserted from an insertion opening into the disk device, and a detecting mechanism for detecting whether an inserted disk is normal.
2. Description of the Related Art
A disk device equipped on a vehicle or the like has a slit-like insertion opening on the front of a casing. A disk inserted from the insertion opening is carried into the device by means of a transfer roller provided in the casing. Then, the disk is held and rotated by a rotating unit provided in the casing or transferred to a disk holder for accommodating multiple disks in the casing. A disk device of this type includes a detecting mechanism for detecting insertion of the disk and detecting whether a normal disk having the diameter of 12 cm is inserted.
A disk device disclosed in Japanese Unexamined Patent Application Publication No. 2007-66351 has a pair of optical detecting elements provided inside an insertion opening. If an optical detecting element detects that a disk inserted from the insertion opening crosses an optical detecting element and then switches its detection output level, a transfer roller is driven in a carry-in direction. In addition, a pair of detecting pins pressed by an outer edge of the carried disk and a pair of switches monitoring motions of each detecting pin, are provided inside the insertion opening. When a normal disk inserted, the pair of detecting pins operate at the same time, so that output levels of both switches are switched.
Further, a distance between the pair of detecting pins is set to prevent such a situation that, when a disk having the diameter of 8 cm is inserted, the pins are both pressed by the outer edge of the disk and output levels of the pair of switches are switched.
A control unit executes the following control process: A predetermined monitoring period is set following the time when a detection output level of the optical detecting element was switched and the transfer roller was driven in the carry-in direction. If output levels of the pair of switches are both switched within the preset predetermined monitoring period, it is determined that a normal disk having the diameter of 12 cm has been inserted, and the disk is directly carried into a casing. Further, if output levels of the pair of switches are not switched within the monitoring period from when a detection output level of the optical detecting element is switched and the transfer roller is driven in the carry-in direction, it is determined that a disk having the diameter of 8 cm, rather than a normal disk, has been inserted. The transfer roller is rotated in the reverse direction to eject the disc.
In the disk device, a disk conveyance distance is determined depending on a positional relationship between an optical detecting element and a pair of switches. The disk conveyance distance is a distance a disk moves during a period from when a detection output level of the optical detecting element is switched until when output levels of the pair of switches are switched. If the conveyance distance is set too long, in the case where a foreign material smaller than the disk having the diameter of 8 cm, such as a credit card or a business card, is inserted, the foreign material goes deep into the device within the monitoring period that is set to monitor the output. In this case, it is likely that the foreign material cannot be removed from the device as a result of coming off the transfer roller, for example.
On the other hand, if a positional relationship between an optical detecting element and a pair of switches is determined so as to reduce the conveyance distance of the foreign object, such as the credit card or a business card, for example, the monitoring period can be reduced. Thus, at the point where the foreign material moves into the casing by a small amount, output levels of the pair of switches can be monitored to detect the foreign material.
However, if the monitoring period set to determine where a normal disk is inserted is too short, in the case where someone holds a normal disk in his hand and slowly inserts the disk, output levels of the pair of switches cannot be both switched within the monitoring period despite the normal disk. As a result, the normal disk tends to be regarded as a foreign material.